1. Field of the Invention
The present invention is in the field of auger type conveyors, and more particularly is directed to an improved dead shaft bearing assembly for an auger type conveyor. Although the dead shaft bearing assembly is anticipated to find its principal utility for use with auger type conveyors, the applicability of the device is not thus limited.
2. The Prior Art
A conventional auger conveyor assembly comprises a trough having an auger member rotatably disposed therein. One end of the auger, typically the end nearest the outfeed station, extends through an end wall of the trough and is connected to a drive mechanism normally including a gear train. The other end of the conveyor is rotatably supported in what is known in the trade as a "dead shaft bearing assembly."
Normally the infeed station is disposed in close proximity to the dead shaft bearing, with the result that pulverulent material deposited in the trough will heap over the shaft bearing. Where the substances processed by the auger are abrasive, or otherwise tend to contaminate the bearing, e.g. finely powdered zinc, sand, sugar, etc., the life of the dead shaft bearing may be extremely short, requiring frequent changes of the bearing. By way of example, where finely powdered zinc is fed, the life of the dead shaft bearing may be as short as 31/2 hours, requiring frequent shutdown and replacement of the bearing assembly.
Two different types of dead shaft bearing assemblies have heretofore been employed.
In one type, a stub shaft projects into the interior of the trough through an end wall. The bearing surface cooperating with the shaft is provided by a bushing sleeved within the tubular pipe assembly on which the auger is mounted. When the bushing becomes worn, replacement thereof mandates removal of the stub shaft, disassembly of the drive connection at the power end of the auger, removal of the auger from the trough, extraction and replacement of the old bushing, and reassembly of the noted parts. The complexity of the described operation requires a substantial amount of down time of the auger. Also, any slight misalignment of the stub shaft accelerates bearing wear.
Despite the drawbacks of the dead shaft bearings of the first type described, they are in common use since they have the advantage that, since no rotating component of the auger assembly extends through the trough end wall, the pulverulent material cannot migrate through the wall.
In a further form of dead shaft bearing, the auger shaft extends through an aperture formed in an end wall of the trough. In such device, a stub shaft carried on a mounting mechanism outside the end wall of the trough extends through the trough and into a bushing disposed in the auger support pipe.
While bearings of the latter type have the advantage and removal and replacement of the bushing does not require disassembly of the auger mechanism, it has the substantial disadvantage that pulverulent materials may readily pass from the trough through the aperture provided for the rotating shaft and contaminate the work area.
There is nothing in either of the described dead shaft bearing constructions which limits ingress of the pulverulent material into the interface between the relatively moving parts. It will be appreciated that the bearing life is drastically reduced where the material is permitted to enter between the moving parts.